Electronic components can have operational properties that can be detrimentally affected by environmental conditions. Such conditions include electromagnetic interference (EMI), vibrations, and particulate and chemical contamination. Consequently, these devices can typically be protected by sealing them in a container that has a cover.
Conventional methods for gasket manufacture include either die-cutting a gasket out of an elastomeric sheet material, or shaping the gasket by injection-molding of an elastomeric mix. Both these methods require expensive tools such as punches and molds which add cost to the final product. Newer manufacturing methods deposit a bead or thread of a fluid elastomer from a nozzle onto a substantially planar surface. The pattern adopted by the fluid elastomer thread can be controlled using automated equipment, programmed so as to provide a gasket having a desired shape. After forming a desired gasket pattern, the fluid elastomer thread can be cured, using heat or light, either at ambient temperatures or in an oven, with or without accelerators or other additives.
Fluid elastomer compositions, suitable for “form-in-place” gaskets using automated applicators, include one or two part silicones, urethane acrylates, and epoxies. These compositions need to have suitable viscosities for automated dispensing from a nozzle, yet be curable to yield a gasket that can have properties such as vibration-damping, electronic shielding, and preventing contamination from outside sources. Additionally the gaskets need to be flexible and resilient.